铝板T型接头背面筋板位置检测方法研究

Research of the Detection Method for T-Type Aluminum Stiffened Panels Welded Joints

采用涡流检测方式检出铝板T型接头背面筋板位置,检测误差范围在0.48 mm之内。欲检测背面筋板位置,线圈所生磁场必须能穿透铝盖板,为此先对待检试件尺寸及线圈内、外径、线径、厚度等参数进行分析,计算了线圈产生的磁场强度分布,确定了线圈尺寸。使用有限元软件comsol仿真不同检测频率下的涡流穿透深度,同时考虑实际工业应用中需有较高的扫查速率,确定了检测频率。设计并制作了检测电路,使用ADuC812单片机为核心,控制AD9854芯片产生正弦激励信号作为载波将背板信号进行调制,再用相敏检波检出背板信号。实际检出波形与所预期结果相符,能清楚判别背面筋板中心位置,误差范围小,本研究拓展了涡流检测技术的应用领域。

Precisely locating T-type welded joints by using eddy current detection method,and the detection error is constrained in less than 0.48 mm. To find the T-type welded joints,the magnetic field generated by eddy current probe must be strong enough to penetrate Al panel,reaching its rear end. Therefore,the dimension of the probe such as inner diameter,outer diameter,thickness and radius of the wire were analyzed for attaining the best results. Then,the dimension of the coil is determined. With the help of FEA software COMSOL,simultaneously considering the high scanning speed in industrial application and depth that magnetic field can reach,the frequency of excitation signal is determined. The detecting circuit have been designed and PCB have been made. Controlled by management core chip ADuC812,chip AD9854 can generate sinusoidal carrier wave which collects T-type welded joints information when scanning,then use phase-sensitive detection method demodulating the welded joints signal. The results show that the detected signal,which contains tiny error,of the welded joints is consistent with what we had anticipated,and the middle line of the welded joints can be recognized evidently. The scope of eddy current detection technique has been developed by this research.